The bare tuna-paste bento was a great success, but with the arrival of my new bento container, I was left with some extra unused space. I decided to fill the space with easy to make and very tasty iri tamago, which is basically a Japanese kind of scrambled eggs! You can definitely use iri tamago in onigiri, or as a small side dish.
You can buy thin beaf slices in some grocery shops or butchers. They may be called minute steaks or quick steaks and are a great ingredient that you can use to make a quick donburi (a rice bowl with meat and vegetable toppings). It's so fast to prepare, that you can do everything in the time it takes to cook the rice!